Airfoils used in gas turbine engines generally have been made from high temperature superalloys given the high temperature operating environment and the various stresses created during operation. Various types of composite materials also have been used given the lightweight nature and the high temperature capabilities of such composite materials. One drawback with such composite materials, however, includes relatively poor interlaminar properties. Moreover, the overall turbine bucket generally may be subject to nonuniform stress patterns under normal operating conditions. As such, the bucket may experience varying degrees of localized stress at different times and at different locations. Turbine buckets therefore may be designed with more composite material at locations such as the shank and the minimum neck areas so as to accommodate high localized tensile stresses.
There is thus a desire for an improved composite materials turbine bucket design. Preferably such an improved turbine bucket design should accommodate increased interlaminar stresses with the use of less material. Such reduced stresses should increase component life while reducing the amount of material also should result in reduced component costs.